feat(storage/vfs): Document context-less API deprecation

docs/en/api-reference/storage/vfs.rst

@@ -19,6 +19,10 @@ FS Registration
 
 To register an FS driver, an application needs to define an instance of the :cpp:type:`esp_vfs_fs_ops_t` structure and populate it with function pointers to FS APIs:
 
+.. warning::
+
+    The API version without a context pointer is deprecated, and will be removed in the future. See :ref:`context_api` for details.
+
 .. highlight:: c
 
 ::
@@ -65,6 +69,7 @@ The recommended approach for registering filesystem is to use statically allocat
         ESP_ERROR_CHECK(esp_vfs_register_fs("/data", &myfs, ESP_VFS_FLAG_DEFAULT, NULL));
     }
 
+.. _context_api:
 
 Context Aware Filesystem
 ^^^^^^^^^^^^^^^^^^^^^^^^

docs/en/migration-guides/release-6.x/6.0/storage.rst

@@ -19,6 +19,7 @@ VFS
 - ``esp_vfs_register_fd_range`` is now considered private and its signature was changed to match the new VFS API style. Projects that still rely on this internal helper must include ``esp_private/socket.h`` and should be aware that the API may change without notice.
 - Legacy VFS APIs (such as ``esp_vfs_register``) that operate on ``esp_vfs_t`` instead of ``esp_vfs_fs_ops_t`` are deprecated and will be removed in the next major release. Switch to the new ``esp_vfs_fs_ops_t``-based APIs.
 - TERMIOS support is now disabled by default. Re-enable :ref:`CONFIG_VFS_SUPPORT_TERMIOS` in menuconfig if your application calls POSIX ``termios`` APIs, such as ``tcsetattr``/``tcgetattr`` for UART configuration.
+- Context-less VFS function pointers are deprecated. Switch to the context-aware ``*_p`` callbacks, register the VFS with ``ESP_VFS_FLAG_CONTEXT_PTR``, and pass ``NULL`` as the context pointer if the driver does not need per-instance state. This change simplifies the API surface and reduces runtime overhead in the VFS call path.
 
 
 ``esp_vfs_console``